1. Field of the Invention
The present invention relates to an image measuring apparatus. Specifically, the present invention relates to a graphical user interface (GUI) supporting an operation by a user to switch between lenses in an image measuring apparatus making use of a microscope that can switch between lenses of various types and magnifications.
2. Description of Related Art
Image measuring apparatuses are known which perform shape observation and dimension measurements of a work piece (measured object) 1 (for example, Japanese Patent No. 3917952, Japanese Patent Laid-open Publication No. 2001-281554). FIG. 14 illustrates a system configuration of an image measuring apparatus. The image measuring apparatus includes an image measuring device (image measurer) 2 and a control computer 50. The image measuring device 2 is equivalent to a microscope. The image measuring device 2 includes a base portion 10, a stage 12, a lens assembly 17, and a CCD camera 3. The base portion 10 includes a foundation 11, and a support rail 16 rising to extend upward from the foundation 11. The work piece (measured object) 1 is placed on the stage 12, which is capable of displacement in X, Y, and rotational directions using an X direction adjustment handle 13, a Y direction adjustment handle 14, and a stage rotation knob 15, respectively.
The lens assembly 17 is supported by the support rail 16 so as to be capable of vertical movement. The lens assembly 17 includes a revolver 18 on a side facing the work piece (measured object) 1, and is configured such that a field lens can be attached and detached with respect to each of a plurality of attachment slots on the revolver 18. In this example, the revolver 18 has four slots. The revolver 18 is rotated electrically or manually, thereby switching between the field lenses. In this example, four field lenses 19a, 19b, 19c, and 19d each having a different magnification power are mounted to the revolver 18.
The lens assembly 17 includes an eyepiece 20 on an upper portion thereof, which the lens assembly 17 connects optically to the field lenses 19a to 19d via an upright trinocular barrel 21. The lens assembly 17 is capable of adjusting vertical movement through manual operation of the handles 22 and 23, or can be electrically driven.
The CCD camera 3 is mounted on the upper portion of the upright trinocular barrel 21.
The control computer 50 includes a host computer 60 and an inputter/outputter 70. The inputter/outputter 70 includes a touch panel display 71, a keyboard 72, and a mouse 73.
The host computer 60 is a computer configured by a CPU and memory. The host computer 60 processes image data obtained by the CCD camera 3 and displays results of the processing on the touch panel display 71. In addition, the host computer 60 switches between the field lenses (19a to 19d) by rotating the revolver 18 in response to an operation input by a user, performs focusing, and the like.
When observing a shape and measuring dimensions of a work piece (measured object) using image measurement, the user must specify which lens is currently being used and instruct the host computer 60 of this information (make a setting on the host computer 60). This is because when a magnification power or the like of the lens currently in use is not specified, the host computer 60 cannot calculate the dimensions of the work piece from the image data.
Given this, a GUI screen such as that shown in FIG. 15, for example, is provided to the user as a screen to input and define lens information. This GUI screen performs display on the touch panel display 71 according to display control performed by the host computer 60. The user performs an information input or selection operation on the GUI screen by performing a touch operation on the touch panel display 71, or by performing keyboard input or mouse operation.
A configuration of the GUI screen shown in FIG. 15 is briefly described. The GUI screen shown in FIG. 15 is referred to as a “lens selection screen 200.” The lens selection screen 200 includes a revolver information display region 210 and a lens information display region 250. The revolver information display region 210 displays which lens is mounted to which slot in the revolver 18. The letters “A,” “B,” “C,” and “D” arranged in a vertical line on a left side of the revolver information display region 210 are identifiers (220) for each slot in the revolver 18. Naturally, the identifiers “A,” “B,” “C,” and “D” for each slot are engraved into the revolver 18, or the like, so as to enable the user to know the identifier for each slot.
Beside each identifier is a lens name display frame 230 corresponding to each identifier. The lens name display frame 230 displays a name (type) of the lens mounted to the corresponding slot in the revolver 18. The user may directly enter the name into the lens name display frame 230 by typing, or may select the lens name from a list provided in a drop-down format. Although not illustrated in detail, when the user clicks on a downward triangle 231 on a right end of each lens name display frame 230, a list of lens names available for use is displayed as a drop-down list. Typically, the user has a stock of various kinds of lenses readily available. When performing image measurement of the work piece, the user selects several (for example, four) lenses to be used in the image measurement from among the stock of readily available lenses and mounts each lens to a slot in the revolver 18. When each lens is mounted to a slot in the revolver 18, the lens name display frame 230 displays which lens is mounted to which slot.
A radio button 240 corresponding to the identifier 220 of each slot is provided between the slot identifier 220 and the lens name display frame 230. The radio button 240 in an ON state (black dot in the center of the circle) represents the slot that is linked to the CCD camera 3, out of all the slots in the revolver 18. In other words, the radio button 240 in the ON state indicates the lens currently being used. The user can switch the lens being used by switching the selection of the radio button 240.
Information for the lens currently being used is displayed in the lens information display region 250. In addition to lens information such as a lens name (251) and a serial number (252), the lens information display region 250 also displays optical performance information (260) and calibration value information (270). The optical performance information 260 includes magnification power 261 and numerical aperture 262. The calibration value information 270 includes actual length per pixel (271) and optical axis offset (inclination of the optical axis) (272). These calibration values are obtained ahead of time, and are input into the host computer 60 and stored. (Although not described in detail, a separate GUI screen may be provided in which the calibration values for each lens are found efficiently, then entered and stored.) When the user selects the lens (changes any of the radio buttons 240 to ON), the host computer 60 retrieves the corresponding lens calibration values from the memory and displays the values in the lens information display region 250.
In a case where the revolver 18 is electric, the revolver 18 rotates automatically in accordance with the lens selection. For example, when the user presses a “CONFIRM” button 201, the revolver 18 automatically rotates such that the lens selected by the radio button 240 becomes usable.
When performing image measurement, correctly setting the calibration values for the lens is essential. When the calibration values are incorrect, an incorrect measured value may be output. Accordingly, although of course the correct calibration values for each lens are found, maintenance and oversight are required to ensure the calibration values remain correct.
In this regard, a scenario is presented in which an image measuring apparatus is used. A user of the image measuring apparatus may be a parts processing company or a research laboratory, for example, where a plurality of people often share use of a single image measuring apparatus. There may be cases where a task of calibrating each lens is always performed by a designated person in charge of calibration, or where the task of calibrating each lens is performed by each user whenever required. In either such case, however, it may be difficult for the various users to know whether calibration has been performed, or whether the registered calibration values are valid. When a lens maintenance log or the like is prepared, the user may be able to tell who performed calibration and when by referring to the log each time. However, this is rather burdensome. In the case of a user who has not mastered using the image measuring apparatus, the user may inadvertently use a lens with incorrect calibration values. Such a mistake may be treated as an erroneous operation for which the user is responsible. However, when the user continues on to subsequent stages of a process based on the incorrect measured values, results are produced which are not favorable for the user, and therefore a mechanism to prevent such erroneous operation from occurring in the first place is still beneficial.